I feel like you are looking at that the wrong way. Me personally, I DO think it's wrong that RG is going to get out soon - very wrong. Especially since he did nothing to help investigators with the case, to confirm 100% who did it with him, since he gave no details and many lies. If he had at least told some truths to help the investigators, I could see how in that case it would warrant a few years taken off. They would have to offer him some incentive to talk, so I don't see how they could have done it any other way. EXCEPT NOW HE DIDN"T TALK AND HE IS STILL GETTING A SHORT SENTENCE. So yes, it's very wrong.
But as for the part about Amanda and Raffaelo, if you look at it from the viewpoint of "they are guilty," then you see where some of us are coming from. They participated in the slaying of a young girl, and yet they're walking around FREE. YES, THEY ARE FREE RIGHT NOW. I don't care about how "miserable" their lives are. They are free to see their families, to live with their boyfriend/girlfriend, to go to parks and restaurants, to go to NYC and other cool places, to travel, to go to school, to eat a nice steak dinner, etc.. Meanwhile, Meredith is gone forever. Does that seem right to you? Why is it so wrong that if someone believes they're guilty, that they find it wrong that that guilty person gets to walk away from the horror that they did. WALK AWAY.
You are looking at it from the viewpoint that they're innocent. That's why it doesn't make sense to you.
JMO